Offa's Dyke Path is a long-distance footpath following closely the Wales–England border. Opened in 1971, it is one of Britain's National Trails and draws walkers from throughout the world. Some of the 177mi route either follows, or keeps close company with, the remnants of Offa's Dyke, an earthwork, most of which was probably constructed in the late 8th century on the orders of Offa of Mercia. However, the dyke does not go over the Black Mountains but follows the current Wales-England border along the Hatterall Ridge.